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Search Results: 1 - 10 of 228265 matches for " John N Plevris "
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Blue mode does not offer any benefit over white light when calculating Lewis score in small-bowel capsule endoscopy
Anastasios Koulaouzidis,Sarah Douglas,John N Plevris
World Journal of Gastrointestinal Endoscopy , 2012, DOI: 10.4253/wjge.v4.i2.33
Abstract: AIM: To check the usefulness of blue mode (BM) review in lewis score (LS) calculation, by comparing it with respective LS results obtained by white light (WL) small-bowel capsule endoscopy (SBCE) review and mucosal inflammation as reflected by faecal calprotectin (FC) levels, considered as ‘gold standard’ for this study. METHODS: Computational analysis of our SBCE database to identify patients who underwent SBCE with PillCam and had FC measured within a 30-day period from their test. Only patients with prior colonoscopy were included, to exclude any colon pathology-associated FC rise. Each small bowel tertile was reviewed (viewing speed 8 fps) with WL and BM, in a back-to-back mode, by a single experienced reviewer. LS were calculated after each WL and BM reviews. Pearson rank correlation (rho, r) statistic was applied. RESULTS: Twenty-seven (n = 27, 20F/7M) patients were included. Thirteen (n = 13) had SBCE with PillCam SB1, and the remainder (n = 14) with PillCam SB2. The median level of FC in this cohort was 125 μg/g. LS (calculated in WL SBCE review) correlation with FC levels was r = 0.490 (P = 0.01), while for BM review and LS correlation with FC was r = 0.472 (P = 0.013). CONCLUSION: Although BM is believed to enhance mucosal details i.e., small mucosal breaks, it did not perform better than WL in the calculation of LS in our cohort.
Human thrombin for the treatment of gastric and ectopic varices
Norma C McAvoy,John N Plevris,Peter C Hayes
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i41.5912
Abstract: AIM: To evaluate the efficacy of human thrombin in the treatment of bleeding gastric and ectopic varices. METHODS: Retrospective observational study in a Tertiary Referral Centre. Between January 1999-October 2005, we identified 37 patients who were endoscopically treated with human thrombin injection therapy for bleeding gastric and ectopic varices. Patient details including age, gender and aetiology of liver disease/segmental portal hypertension were documented. The thrombin was obtained from the Scottish National Blood Transfusion Service and prepared to give a solution of 250 IU/mL which was injected via a standard injection needle. All patient case notes were reviewed and the total dose of thrombin given along with the number of endoscopy sessions was recorded. Initial haemostasis rates, rebleeding rates and mortality were catalogued along with the incidence of any immediate complications which could be attributable to the thrombin therapy. The duration of follow up was also listed. The study was conducted according to the United Kingdom research ethics guidelines. RESULTS: Thirty-seven patients were included. 33 patients (89%) had thrombin (250 U/mL) for gastric varices, 2 (5.4%) for duodenal varices, 1 for rectal varices and 1 for gastric and rectal varices. (1) Gastric varices, an average of 15.2 mL of thrombin was used per patient. Re-bleeding occurred in 4 patients (10.8%), managed in 2 by a transjugular intrahepatic portosystemic shunt (TIPSS) (one unsuccessfully who died) and in other 2 by a distal splenorenal shunt; (2) Duodenal varices (or type 2 isolated gastric varices), an average of 12.5 mL was used per patient over 2-3 endoscopy sessions. Re-bleeding occurred in one patient, which was treated by TIPSS; and (3) Rectal varices, an average of 18.3 mL was used per patient over 3 endoscopy sessions. No re-bleeding occurred in this group. CONCLUSION: Human thrombin is a safe, easy to use and effective therapeutic option to control haemorrhage from gastric and ectopic varices.
Update of endoscopy in liver disease: More than just treating varices
Christoforos Krystallis,Gail S Masterton,Peter C Hayes,John N Plevris
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i5.401
Abstract: The management of complications in liver disease is often complex and challenging. Endoscopy has undergone a period of rapid expansion with numerous novel and specialized endoscopic modalities that are of increasing value in the investigation and management of the patient with liver disease. In this review, relevant literature search and expert opinions have been used to provide a brief overview and update of the current endoscopic management of patients with liver disease and portal hypertension. The main areas covered are safety of endoscopy in patients with liver disease, the use of standard endoscopy for the treatment of varices and the role of new endoscopic modalities such as endoscopic ultrasound, esophageal capsule, argon plasma coagulation, spyglass and endomicroscopy in the investigation and treatment of liver-related gastrointestinal and biliary pathology. It is clear that the role of the endoscopy in liver disease is well beyond that of just treating varices. As the technology in endoscopy expands, so does the role of the endoscopist in liver disease.
Impaired gluconeogenesis in a porcine model of paracetamol induced acute liver failure
Konstantinos J Dabos, Henry R Whalen, Philip N Newsome, John A Parkinson, Neil C Henderson, Ian H Sadler, Peter C Hayes, John N Plevris
World Journal of Gastroenterology , 2011,
Abstract: AIM: To investigate glucose homeostasis and in particular gluconeogenesis in a large animal model of acute liver failure (ALF).METHODS: Six pigs with paracetamol induced ALF under general anaesthesia were studied over 25 h. Plasma samples were withdrawn every five hours from a central vein. Three animals were used as controls and were maintained under anaesthesia only. Using 1H NMR spectroscopy we identified most gluconeogenic amino acids along with lactate and pyruvate in the animal plasma samples.RESULTS: No significant changes were observed in the concentrations of the amino acids studied in the animals maintained under anaesthesia only. If we look at the ALF animals, we observed a statistically significant rise of lactate (P < 0.003) and pyruvate (P < 0.018) at the end of the experiments. We also observed statistically significant rises in the concentrations of alanine (P < 0.002), glycine (P < 0.005), threonine (P < 0.048), tyrosine (P < 0.000), phenylalanine (P < 0.000) and isoleucine (P < 0.01). Valine levels decreased significantly (P < 0.05).CONCLUSION: Our pig model of ALF is characterized by an altered gluconeogenetic capacity, an impaired tricarboxylic acid (TCA) cycle and a glycolytic state.
Development of an invasively monitored porcine model of acetaminophen-induced acute liver failure
Philip N Newsome, Neil C Henderson, Leonard J Nelson, Costas Dabos, Celine Filippi, Chris Bellamy, Forbes Howie, Richard E Clutton, Tim King, Alistair Lee, Peter C Hayes, John N Plevris
BMC Gastroenterology , 2010, DOI: 10.1186/1471-230x-10-34
Abstract: 35kg pigs were maintained under general anaesthesia and invasively monitored. Control pigs received a saline infusion, whereas ALF pigs received acetaminophen intravenously for 12 hours to maintain blood concentrations between 200-300 mg/l. Animals surviving 28 hours were euthanased.Cytochrome p450 levels in phenobarbital pre-treated animals were significantly higher than non pre-treated animals (300 vs 100 pmol/mg protein). Control pigs (n = 4) survived 28-hour anaesthesia without incident. Of nine pigs that received acetaminophen, four survived 20 hours and two survived 28 hours. Injured animals developed hypotension (mean arterial pressure; 40.8 +/- 5.9 vs 59 +/- 2.0 mmHg), increased cardiac output (7.26 +/- 1.86 vs 3.30 +/- 0.40 l/min) and decreased systemic vascular resistance (8.48 +/- 2.75 vs 16.2 +/- 1.76 mPa/s/m3). Dyspnoea developed as liver injury progressed and the increased pulmonary vascular resistance (636 +/- 95 vs 301 +/- 26.9 mPa/s/m3) observed may reflect the development of respiratory distress syndrome.Liver damage was confirmed by deterioration in pH (7.23 +/- 0.05 vs 7.45 +/- 0.02) and prothrombin time (36 +/- 2 vs 8.9 +/- 0.3 seconds) compared with controls. Factor V and VII levels were reduced to 9.3 and 15.5% of starting values in injured animals. A marked increase in serum AST (471.5 +/- 210 vs 42 +/- 8.14) coincided with a marked reduction in serum albumin (11.5 +/- 1.71 vs 25 +/- 1 g/dL) in injured animals. Animals displayed evidence of renal impairment; mean creatinine levels 280.2 +/- 36.5 vs 131.6 +/- 9.33 μmol/l. Liver histology revealed evidence of severe centrilobular necrosis with coagulative necrosis. Marked renal tubular necrosis was also seen. Methaemoglobin levels did not rise >5%. Intracranial hypertension was not seen (ICP monitoring), but there was biochemical evidence of encephalopathy by the reduction of Fischer's ratio from 5.6 +/- 1.1 to 0.45 +/- 0.06.We have developed a reproducible large animal model of acetaminophen-i
Novel immortalized human fetal liver cell line, cBAL111, has the potential to differentiate into functional hepatocytes
Tanja Deurholt, Niek P van Til, Aniska A Chhatta, Lysbeth ten Bloemendaal, Ruth Schwartlander, Catherine Payne, John N Plevris, Igor M Sauer, Robert AFM Chamuleau, Ronald Elferink, Jurgen Seppen, Ruurdtje Hoekstra
BMC Biotechnology , 2009, DOI: 10.1186/1472-6750-9-89
Abstract: Cell clones derived from human fetal liver cells were immortalized by over-expression of telomerase reverse transcriptase. The resulting cell line, cBAL111, displayed hepatic functionality similar to the parental cells prior to immortalization, and did not grow in soft agar. Cell line cBAL111 expressed markers of immature hepatocytes, like glutathione S transferase and cytokeratin 19, as well as progenitor cell marker CD146 and was negative for lidocaine elimination. On the other hand, the cBAL111 cells produced urea, albumin and cytokeratin 18 and eliminated galactose. In contrast to hepatic cell lines NKNT-3 and HepG2, all hepatic functions were expressed in cBAL111, although there was considerable variation in their levels compared with primary mature hepatocytes. When transplanted in the spleen of immunodeficient mice, cBAL111 engrafted into the liver and partly differentiated into hepatocytes showing expression of human albumin and carbamoylphosphate synthetase without signs of cell fusion.This novel liver cell line has the potential to differentiate into mature hepatocytes to be used for in vitro hepatocyte applications.Most pharmacological or toxicological assays and bioartificial liver support systems require fully differentiated hepatocytes. The availability of mature human hepatocytes is variable and the numbers low, because they are usually isolated from donor livers not suitable for transplantation. In addition these cells hardly proliferate in vitro [1,2]. Since mature human hepatocytes cannot be used for large-scale applications, there is a pressing need for a cell line that combines highly differentiated hepatic functions while maintaining adequate proliferation capacity.Several cell lines derived from human liver tumours, such as the hepatoma cell line HepG2 [3], as well as in vitro immortalized cell lines, like the NKNT-3 cell line, have been investigated [4,5]. In general, these cell lines proliferate adequately, but the levels of hepatocyte-specif
Structural optimization considering the probabilistic system response
Papadrakakis M.,Lagaros N.D.,Plevris V.
Theoretical and Applied Mechanics , 2004, DOI: 10.2298/tam0404361p
Abstract: In engineering problems, the randomness and uncertainties are inherent and the scatter of structural parameters from their nominal ideal values is unavoidable. In Reliability Based Design Optimization (RBDO) and Robust Design Optimization (RDO) the uncertainties play a dominant role in the formulation of the structural optimization problem. In an RBDO problem additional non deterministic constraint functions are considered while an RDO formulation leads to designs with a state of robustness, so that their performance is the least sensitive to the variability of the uncertain variables. In the first part of this study a metamodel assisted RBDO methodology is examined for large scale structural systems. In the second part an RDO structural problem is considered. The task of robust design optimization of structures is formulated as a multi-criteria optimization problem, in which the design variables of the optimization problem, together with other design parameters such as the modulus of elasticity and the yield stress are considered as random variables with a mean value equal to their nominal value. .
A Solution of Kepler’s Equation  [PDF]
John N. Tokis
International Journal of Astronomy and Astrophysics (IJAA) , 2014, DOI: 10.4236/ijaa.2014.44062
Abstract: The present study deals with a traditional physical problem: the solution of the Kepler’s equation for all conics (ellipse, hyperbola or parabola). Solution of the universal Kepler’s equation in closed form is obtained with the help of the two-dimensional Laplace technique, expressing the universal functions as a function of the universal anomaly and the time. Combining these new expressions of the universal functions and their identities, we establish one biquadratic equation for universal anomaly (χ) for all conics; solving this new equation, we have a new exact solution of the present problem for the universal anomaly as a function of the time. The verifying of the universal Kepler’s equation and the traditional forms of Kepler’s equation from this new solution are discussed. The plots of the elliptic, hyperbolic or parabolic Keplerian orbits are also given, using this new solution.
Measurement of Arsenic Species in Infant Rice Cereals by Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry  [PDF]
John D. Brockman, John W. N. Brown IV
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.310091
Abstract: Infant rice cereals were analyzed for total arsenic, inorganic arsenic (i-As) and the organic arsenic species monomethylarsonoic acid (MMA) and dimethylarsinic acid (DMA) using liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS). Total arsenic concentrations in the samples ranged from 110 ng/gup to 420 ng/g. The i-As in the rice cereals accounted for 33% to 77% of the total arsenic. The observed variability between infant rice cereals makes a dietary survey approach to accessing arsenic exposures difficult.
New Investigative Findings from the Debiased Converted-Measurement Kalman Filter  [PDF]
John N. Spitzmiller, Reza R. Adhami
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.27053
Abstract: The original algorithm for the 2-D debiased converted-measurement Kalman filter (CMKF) specified, with incorrect mathematical justification, a requirement for evaluating the average true bias and covari-ance with the best available polar estimate, rather than exclusively with the polar measurement. Even though this original algorithm yields better tracking performance than the debiased-CMKF algorithm which evaluates the average true bias and covariance exclusively with the polar measurement, this paper shows the specified requirement compromises the statistical consistency between the debiased converted measurement’s error and the average true covariance. To resolve this apparent contradiction, this paper provides the correct empirical explanation for the tracking-performance improvement obtained by the specified requirement.
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